/*  Copyright  2009
 *  @Author
 *  Richard Changde Yin            e-mail yinchangde@hotmail.com
 *
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; version 2 of the License.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */

/*
* @filename : func.h
*/
#ifndef COLLAPSAR_FUNCTION_FUNC_H
#define COLLAPSAR_FUNCTION_FUNC_H

/// TODO: Rename this file - func.h is stupid.

#include <item.h>
#include <sql_list.h>
#include <item/bin_string.h>


class Item_func :public Item_result_field
{
protected:
  Item **args, *tmp_arg[2];
  /*
    Allowed numbers of columns in result (usually 1, which means scalar value)
    0 means get this number from first argument
  */
  uint32_t allowed_arg_cols;
public:

  using Item::split_sum_func;

  uint32_t arg_count;
  table_map used_tables_cache, not_null_tables_cache;
  bool const_item_cache;
  enum Functype { UNKNOWN_FUNC,EQ_FUNC,EQUAL_FUNC,NE_FUNC,LT_FUNC,LE_FUNC,
                  GE_FUNC,GT_FUNC,
                  LIKE_FUNC,ISNULL_FUNC,ISNOTNULL_FUNC,
                  COND_AND_FUNC, COND_OR_FUNC, COND_XOR_FUNC,
                  BETWEEN, IN_FUNC, MULT_EQUAL_FUNC,
                  INTERVAL_FUNC, ISNOTNULLTEST_FUNC,
                  NOT_FUNC, NOT_ALL_FUNC,
                  NOW_FUNC, TRIG_COND_FUNC,
                  SUSERVAR_FUNC, GUSERVAR_FUNC, COLLATE_FUNC,
                  EXTRACT_FUNC, CHAR_TYPECAST_FUNC, FUNC_SP,
                  NEG_FUNC };
  enum optimize_type { OPTIMIZE_NONE,OPTIMIZE_KEY,OPTIMIZE_OP, OPTIMIZE_NULL,
                       OPTIMIZE_EQUAL };
  enum Type type() const { return FUNC_ITEM; }
  virtual enum Functype functype() const   { return UNKNOWN_FUNC; }
  Item_func(void):
    allowed_arg_cols(1), arg_count(0)
  {
    with_sum_func= 0;
  }
  Item_func(Item *a):
    allowed_arg_cols(1), arg_count(1)
  {
    args= tmp_arg;
    args[0]= a;
    with_sum_func= a->with_sum_func;
  }
  Item_func(Item *a,Item *b):
    allowed_arg_cols(1), arg_count(2)
  {
    args= tmp_arg;
    args[0]= a; args[1]= b;
    with_sum_func= a->with_sum_func || b->with_sum_func;
  }
  Item_func(Item *a,Item *b,Item *c):
    allowed_arg_cols(1)
  {
    arg_count= 0;
    if ((args= (Item**) sql_alloc(sizeof(Item*)*3)))
    {
      arg_count= 3;
      args[0]= a; args[1]= b; args[2]= c;
      with_sum_func= a->with_sum_func || b->with_sum_func || c->with_sum_func;
    }
  }
  Item_func(Item *a,Item *b,Item *c,Item *d):
    allowed_arg_cols(1)
  {
    arg_count= 0;
    if ((args= (Item**) sql_alloc(sizeof(Item*)*4)))
    {
      arg_count= 4;
      args[0]= a; args[1]= b; args[2]= c; args[3]= d;
      with_sum_func= a->with_sum_func || b->with_sum_func ||
        c->with_sum_func || d->with_sum_func;
    }
  }
  Item_func(Item *a,Item *b,Item *c,Item *d,Item* e):
    allowed_arg_cols(1)
  {
    arg_count= 5;
    if ((args= (Item**) sql_alloc(sizeof(Item*)*5)))
    {
      args[0]= a; args[1]= b; args[2]= c; args[3]= d; args[4]= e;
      with_sum_func= a->with_sum_func || b->with_sum_func ||
        c->with_sum_func || d->with_sum_func || e->with_sum_func ;
    }
  }
  Item_func(List<Item> &list);
  // Constructor used for Item_cond_and/or (see Item comment)
  Item_func(Session *session, Item_func *item);
  bool fix_fields(Session *, Item **ref);
  void fix_after_pullout(Select_Lex *new_parent, Item **ref);
  table_map used_tables() const;
  table_map not_null_tables() const;
  void update_used_tables();
  bool eq(const Item *item, bool binary_cmp) const;
  virtual optimize_type select_optimize() const { return OPTIMIZE_NONE; }
  virtual bool have_rev_func() const { return 0; }
  virtual Item *key_item() const { return args[0]; }
  /*
    This method is used for debug purposes to print the name of an
    item to the debug log. The second use of this method is as
    a helper function of print(), where it is applicable.
    To suit both goals it should return a meaningful,
    distinguishable and sintactically correct string.  This method
    should not be used for runtime type identification, use enum
    {Sum}Functype and Item_func::functype()/Item_sum::sum_func()
    instead.
  */
  virtual const char *func_name() const { return NULL; };
  virtual bool const_item() const { return const_item_cache; }
  Item **arguments() const { return args; }
  void set_arguments(List<Item> &list);
  uint32_t argument_count() const { return arg_count; }
  void remove_arguments() { arg_count=0; }
  virtual void split_sum_func(Session *session, Item **ref_pointer_array,
                              List<Item> &fields);

  virtual void print(String *str, enum_query_type query_type);
  void print_op(String *str, enum_query_type query_type);
  void print_args(String *str, uint32_t from, enum_query_type query_type);
  virtual void fix_num_length_and_dec();
  void count_only_length();
  void count_real_length();
  void count_decimal_length();

  bool get_arg0_date(COLLAPSAR_TIME *ltime, uint32_t fuzzy_date);
  bool get_arg0_time(COLLAPSAR_TIME *ltime);

  bool is_null();

  void signal_divide_by_null();

  virtual Field *tmp_table_field() { return result_field; }
  virtual Field *tmp_table_field(Table *t_arg);

  Item *get_tmp_table_item(Session *session);

  my_decimal *val_decimal(my_decimal *);

  bool agg_arg_collations(DTCollation &c, Item **items, uint32_t nitems,
                          uint32_t flags);
  bool agg_arg_collations_for_comparison(DTCollation &c,
                                         Item **items, uint32_t nitems,
                                         uint32_t flags);
  bool agg_arg_charsets(DTCollation &c, Item **items, uint32_t nitems,
                        uint32_t flags, int item_sep);
  bool walk(Item_processor processor, bool walk_subquery, unsigned char *arg);

  Item *transform(Item_transformer transformer, unsigned char *arg);

  Item* compile(Item_analyzer analyzer, unsigned char **arg_p,

                Item_transformer transformer, unsigned char *arg_t);
  void traverse_cond(Cond_traverser traverser,
                     void * arg, traverse_order order);
  double fix_result(double value);

};


#endif /*COLLAPSAR_FUNCTION_FUNC_H*/
